946 resultados para the least number heuristic
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The 2014 Ebola virus (EBOV) outbreak in West Africa is the largest outbreak of the genus Ebolavirus to date. To better understand the spread of infection in the affected countries, it is crucial to know the number of secondary cases generated by an infected index case in the absence and presence of control measures, i.e., the basic and effective reproduction number. In this study, I describe the EBOV epidemic using an SEIR (susceptible-exposed-infectious-recovered) model and fit the model to the most recent reported data of infected cases and deaths in Guinea, Sierra Leone and Liberia. The maximum likelihood estimates of the basic reproduction number are 1.51 (95% confidence interval [CI]: 1.50-1.52) for Guinea, 2.53 (95% CI: 2.41-2.67) for Sierra Leone and 1.59 (95% CI: 1.57-1.60) for Liberia. The model indicates that in Guinea and Sierra Leone the effective reproduction number might have dropped to around unity by the end of May and July 2014, respectively. In Liberia, however, the model estimates no decline in the effective reproduction number by end-August 2014. This suggests that control efforts in Liberia need to be improved substantially in order to stop the current outbreak.
Rapid drop in the reproduction number during the Ebola outbreak in the Democratic Republic of Congo.
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The Democratic Republic of Congo (DRC) experienced a confined rural outbreak of Ebola virus disease (EVD) with 69 reported cases from July to October 2014. Understanding the transmission dynamics during the outbreak can provide important information for anticipating and controlling future EVD epidemics. I fitted an EVD transmission model to previously published data of this outbreak and estimated the basic reproduction number R 0 = 5.2 (95% CI [4.0-6.7]). The model suggests that the net reproduction number Rt fell below unity 28 days (95% CI [25-34] days) after the onset of symptoms in the index case. This study adds to previous epidemiological descriptions of the 2014 EVD outbreak in DRC, and is consistent with the notion that a rapid implementation of control interventions helped reduce further spread.
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Countries classified as least developed countries (LDCs) were granted duty-free quota-free (DFQF) access to the Japanese market. This study examines the impact of that access and finds that, in general, it did not benefit the LDCs. The construction of concordance tables for Japan's 9 digit tariff line codes enables analysis at the tariff line level, which overcomes a possible aggregation bias. The exogenous nature of DFQF access mitigates the endogeneity problem. Various estimation models, including the triple difference estimator, show that in general the LDCs did not benefit from DFQF access to the Japanese market. The total value of imports from LDCs has been increasing, but the imports granted both zero tariffs and substantial preference margins over non-LDC countries were not successful. These findings suggest that for LDCs the tariff barrier is a relatively small obstacle: Trade is affected more strongly by other factors, such as infrastructure, nontariff barriers, geographic distance, and cultural differences.
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Mode of access: Internet.
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"Proof edition."
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Bibliography: p. 430-433.
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Mode of access: Internet.
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Cornell Aeronautical Laboratory, Inc., Buffalo. Report no. AA-1948-Y-3
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Mode of access: Internet.
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Much of the origin of this document attributed to the Pennsylvania Dept. of Education, Bureau of Special Education and the National Learning Resource Center of Pennsylvania.